Pulse stretch and delay

[elki]

Hello! I am having a hard time understanding why this simple circuit based on 74HC123 does not work in practice, while the simulation results are as expected. I am getting exactly the same stretched pulse, but somehow, I am not succeeding in introducing a delay. Any ideas? Maybe there are some practical considerations to take into account?

[Andree Henkel]

maybe problem is that the Cx Input Pins are basiscally floating - there is no DC connection to 5V or Gnd. Try connect a rather high value resistor, maybe 1MOhm to one of the rails at each of both Cx inputs.

[Benta]

CX has to be grounded externally as well. And where are your decoupling caps?

[elki]

Thanks. Sorry for the newbie question: what do you mean exactly by CX grounding? How do you propose to modify the circuit?
I have the decoupling caps on the power supply rail (not shown in the schematics, sorry).

CX has to be grounded externally as well. And where are your decoupling caps?

[Benta]

Sorry for the newbie question: what do you mean exactly by CX grounding?

Just connect the CX pins to ground (or 0 V, if you like that term better).